Thermoset Polyimide (PI)
Thermoset PI is a thermoset plastic. The properties of thermoset PI include five common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare thermoset PI to other thermoset plastics (top) and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.
Mechanical Properties
Compressive (Crushing) Strength
120 to 210 MPa 17 to 31 x 103 psi
Elongation at Break
2.0 to 5.9 %
Flexural Modulus
3.1 to 4.8 GPa 0.45 to 0.7 x 106 psi
Flexural Strength
60 to 100 MPa 8.7 to 14 x 103 psi
Impact Strength: Notched Izod
21 to 43 J/m 0.4 to 0.8 ft-lb/in
Tensile Strength: Ultimate (UTS)
37 to 81 MPa 5.4 to 12 x 103 psi
Thermal Properties
Glass Transition Temperature
360 °C 680 °F
Heat Deflection Temperature At 1.82 MPa (264 psi)
370 °C 700 °F
Maximum Temperature: Autoignition
380 °C 720 °F
Maximum Temperature: Decomposition
330 °C 630 °F
Maximum Temperature: Mechanical
260 °C 500 °F
Specific Heat Capacity
1130 J/kg-K 0.27 BTU/lb-°F
Thermal Conductivity
0.29 to 1.7 W/m-K 0.17 to 1.0 BTU/h-ft-°F
Thermal Expansion
38 to 54 µm/m-K
Electrical Properties
Dielectric Constant (Relative Permittivity) At 1 MHz
3.1
Dielectric Strength (Breakdown Potential)
20 kV/mm 0.78 V/mil
Electrical Resistivity Order of Magnitude
15 10x Ω-m
Otherwise Unclassified Properties
Density
1.4 to 1.6 g/cm3 87 to 100 lb/ft3
Limiting Oxygen Index (LOI)
40 %
Water Absorption After 24 Hours
0.14 to 0.24 %
Water Absorption At Saturation
3.6 %
Common Calculations
Strength to Weight: Axial
6.5 to 16 points
Strength to Weight: Bending
16 to 30 points
Thermal Diffusivity
0.18 to 0.95 mm2/s
Followup Questions
Further Reading
ASTM D6456: Standard Specification for Finished Parts Made from Polyimide Resin
Thermosets: Structure, Properties and Applications, Qipeng Guo (editor), 2012
Reinforced Plastics Durability, Geoffrey Pritchard (editor), 1999
Modern Plastics Handbook, Charles A. Harper (editor), 1999
Plastics Materials, 7th ed., J. A. Brydson, 1999
CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015